Music has been Manchester's best-known export in recent decades, and the thieves knew what would sell.

Mark Taylor, the managing director of the chain of north-west stores, said: "It's all hi-tech equipment for making music through computers. Its expensive, portable and obviously highly desirable."

Pointing at empty racks, Taylor said: "All the synthesisers have been stolen, and the portable keyboards.

"I think the immediate reaction was anger, and frustration at not being able to do anything last night. But that's been balanced by the positive responses of our staff and our landlord."

Businesses in central Manchester are preparing for a repeat of the violence, which saw youths setting fire to a branch of Miss Selfridge and raiding shops selling trainers, jewellery and electronics.

At a branch of Jessops, the camera chain, which survived unscathed last night, store managers were preparing to board the shop up again tonight.

Manager Johnny Tighe said: "We moved high value stock off the shopfloor and put wooden boards up over the windows by 6pm".

Fellow manager Andy Porter praised the police. "I think they saw what happened down south and reacted quickly," he said.

Neil Mutter, 58, the owner of the family-run jewellery shop AE Mutter, established in 1884 in the city's Northern Quarter, said: "I feel remarkably calm. We clean up and smile. I feel glad that the other businesses in the area haven't been targeted. Our customers have been brilliant. They have been calling in saying they have video of the people who did it and offering to help."

The damage to the city's business district was widespread, ranging in scale from a few shattered windows to shops that had in effect been gutted – evidence of the fluid contest between looters and the police on Tuesday night.

In Piccadilly Gardens, where youths confronted the police at night, hundreds of volunteers gathered with brooms in the morning to clean up.

Much of the work had already been done by municipal staff who volunteered their time overnight.

Carl Austin, in an "I heart MCR" T-shirt, said: "We've come out not so much to clean up but to show solidarity. This isn't political. Its just youth running riot."

Fellow volunteer Alice Hess, 20, said: "The atmosphere is really positive ... I want to show the same generation who damaged the city is also capable of clearing it up."

Addressing a crowd who gathered in Piccadilly Gardens, police faced calls for the looters to be sternly punished, whatever their age.

"They shouldn't just get away with a slap," said Paul Gaines, 54.

Assistant Chief Constable Garry Shewan told the crowd: "The people who acted violently last night have to go to court and face the consequences."

He urged the public to face down looters: "We need crowds of people to say: 'Not in our city'."

Greater Manchester police have now arrested more than 100 people. The majority were arrested on suspicion of criminal damage while about 17 were arrested for public order offences. They are aged between 15 and 58. Seven of those detained were under 18, police said.

In a statement, Shewan said: "Last night's shameful destruction saw some of the worst scenes I have ever witnessed as a police officer. What we have seen are serious and unprecedented levels of violence and criminality on Greater Manchester's streets. These are shameful actions from criminals who have attacked our cities."

Councillor Pat Karney said: "The true face of Manchester has come out this morning. People are volunteering to clean the city up and get the city back to work."